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3/20/11

Nuke reactor stabilising

The image released by the Japanese Ground Self-Defence Forces show a fire engine dousing reactor number 3 in an effort to cool it at the Fukushima Daiichi nuclear power station on Friday.

One of six tsunami-crippled nuclear reactors appeared to stabilise yesterday as Japan raced to restore power to the stricken power plant to cool it and prevent a greater catastrophe.Engineers reported some rare success after fire trucks sprayed water for about three hours on reactor No. 3, widely considered the most dangerous at the ravaged Fukushima Daiichi nuclear complex because of its use of highly toxic plutonium.

"The situation there is stabilising somewhat," Chief Cabinet Secretary Yukio Edano told a news conference. Engineers earlier attached a power cable to the outside of the mangled plant in a desperate attempt to get water pumps going that would cool overheating fuel rods and prevent a deadly radiation leak.
They hope electricity will flow by today to four reactors in the complex about 240km north of here. Prime Minister Naoto Kan, facing Japan's biggest disaster since World War 2, sounded out the opposition about forming a government of national unity to deal with a crisis that has left more than 7,000 people confirmed dead and turned whole towns into waterlogged, debris-strewn wastelands with another 10,700 people missing.

The disaster has sent a shock through global financial markets, with major economies joining forces to calm the Japanese yen.
Officials connected a power cable to the No. 2 reactor and planned to test power in reactors No. 1, 2, 3 and 4 today. Working inside a 20km evacuation zone at Fukushima, nearly 300 engineers got a second diesel generator attached to reactor No. 6 working, the nuclear safety agency said. They used the power to restart cooling pumps on No. 5.

"TEPCO has connected the external transmission line with the receiving point of the plant and confirmed that electricity can be supplied," the plant's operator, Tokyo Electric Power Co, said in a statement. Nearly 1.5km of cable is being laid before engineers try to crank up the coolers at reactor No. 2, followed by numbers 1, 3 and 4 this weekend, company officials said.

"If they are successful in getting the cooling infrastructure up and running, that will be a significant step forward in establishing stability," said Eric Moore, a nuclear power expert at US-based FocalPoint Consulting Group.
If that fails, one option is to bury the sprawling 40-year-old plant in sand and concrete to prevent a catastrophic radiation release. The method was used at the Chernobyl reactor in 1986, scene of the world's worst nuclear reactor disaster.

Underlining authorities' desperation, fire trucks sprayed water overnight in a crude tactic to cool reactor No. 3, considered the most critical because of its use of mixed oxides, or mox, containing both uranium and highly toxic plutonium.

Japan has raised the severity rating of the nuclear crisis to level 5 from 4 on the seven-level INES international scale. Chernobyl, in Ukraine, was a 7 on that scale.

The operation to avert large-scale radiation has overshadowed the humanitarian crisis caused by the 9.0-magnitude quake and 10m tsunami.

Health officials and the United Nations atomic watchdog have said radiation levels in the capital were not harmful. But the city has seen an exodus of tourists, expatriates and many Japanese, who fear a blast of radioactive material.

Officials asked people in the 20km "take cover" zone to follow some directives when going outside: Drive, don't walk. Wear a mask. Wear long sleeves. Don't go out in the rain. Though there has been alarm around the world, experts say dangerous levels of radiation are unlikely to spread to other nations.

Amid their distress, Japanese took time to laud the 279 nuclear plant workers toiling in the nuclear plant's wreckage, wearing masks, goggles and protective suits sealed by duct tape.

"My eyes well with tears at the thought of the work they are doing," Kazuya Aoki, a safety official at Japan's Nuclear and Industrial Safety Agency, said.